Telephone system.



H. D. CURRIER.

TELEPHONE SYSTEM. APPLICATION FILED JULY 21. i914.

LWLWU. Patented A rqs, 191?.

earned are sarnrns i a rnn r ornrcn HIRAM D. CUBRIERY', OF CHICAGO, ILLINOIS, ASSIGNOR T0 KELLOGG SWITCHBOAED AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINUIS.

TELEPHONE SYSTEM.

To an whom it may concern:

Be it known that l, H nAM D. Gunmen, a citizen of the United States of America, re-

' siding in Chicago, county of Cook, and

and simplified circuit arrangement for ordering connections Which are to be extended from any subscribers cord circuit through a trunk circuit to subscribers lines in a distantv exchanger The general practice now followed in Iran dlin'g trunk calls in multi-exchange systems is for the A operator to communicate by means of a special orderwirecircuit with a trunk operator in the. desired distant exchange who receives the number of the wanted line from the A-operator and then assigns a trunk to which the A-operator has access whereupon the A-operator connects the calling line with the assigned trunk and the B or trunk operator extends such trunk to the jack of the wanted line., In systems of this character so-c'alled A and B operators are employed and separate and distinct orderwire and trunk circuits are employed and one of the features of my invention is the provision of 'a control circuit associated with the subscribers cord circuit whereby the originating operator, after inserting the calling plug in a trunk selected by her uses this connection as an orderWire preferably by throwing a special orderwire key which severs the cord circuit and connects her telephone set with the calling end of the cord. Thus the originating operator may pass the call to the distant operator and does so without the calling subscriber hearing the order when it is passed. I also preferably make this orderwire key of the two-waytype so that when thrown one way the orderwire circuit is connected and when thrown the other .way a recall circuit is established.

For a better understanding of my invention, reference willbe had to the accompanying drawing in which a calling substation A Specification of Letters Patent, 7

Patented Apr, 3 ill vl'to Application filed July 27, 1914. Serial No. 853,285.

and called substation D are shown terminating in line circuits L and L respectively at different exchanges, together with an operators cord circuit B and a trunk circuit 0. The substations A and D are of a wellknown common battery type and chosen for the purpose of illustration, said substations terminatin in line circuits L includin line and cut-off relays LR and CO respectively. Multiply connected jacks J are provided and in the present embodiment of my invention a linesignal S is providedfor each jack, the jacks being distributed among different 0perators; That is, when a call is initiated over any H1135 the linesignalsS are lighted and anyone of a p'lnrality of operators can seize the call.

answer a call seizes it to the exclusion of any subsequent operator. That is, when the first plug AP is connected to a calling line, the sleeverelay AS associated therewith is connected to the sleeve strand and should a second operator'attempt to seize this call the high resistance relay TE of the second cord circuit can not operate and this prevents the second operator from connecting to this line. An answering tip relay AT is also associated with the answering end of the cord being connected with the tip strand. I have also provided an instantaneous recall arrangement including a link disconnect relay LD. Should a callingisubscriber desireto recall as soon as his reremoval of the operators cord B. from his line the replacing of ihisreceiver energizes the link disconnect relay LD thereby disconnecting relays AT and AS sothat the sub sequent removal of his receiver will :again i light his line lamp so that the recall may be seized by the same or a diiferent operator.

- In connection with the calling end of circuitB, Iprovide a calling sleeve relay CS anda calling tiprelay CT which are operated in a well-know'n-manner. vAutomaticpartyline ringing is also provided and to thislend I have provided a party line key RK'together with a ringing'control relay RGR which-is: energized when; the ringing key is actuated together with an interrupter relay IR which alternately connects ringin generator and calling tip relay GT of'the called line. A call register is also provided comprising ameter relay, and meter magnet .MM which are oontrolled through common contacts of the, ringing keyg I' also provide automatic listening and disconnectingythe operatorls cord circuit 0 being 'connected to the cord circuit through the sleeve relay AS when connection is made to acalling lineand again, disconnected by the operation of sleeve relay CS when connect'ionj is extended to another line or a trunk jack. I i y I In order'to handle the recalls and trunking connections I preferably provide a'twoway key including the recall contacts RE andthe orderwire contacts OW. This'key when: thrown one wayfbeing adapted to operateficontacts RE toconnect the opera torstelephone set 0 with the cord circuit and "at, the; same. time restore the link disconnect relay LD, and when. the key is thrown in. theother direction the orderwire contacts OW are actuated to first sever-the talking. conductors of; the cord circuit and then'connect the operators telephone 0 to the callingend of the cord whereby the operator may converse with the operator to whom the trunk connection is being extended: and: at the same time subscriber from hearing the distant; operator. .7

'gNolw ,as-;to, :the'*trunk circuit 0,1 preferablyprovide a number of multiply jconnectedtr'unkfljacks TJ for each trunk and distribute thesejacksamong diflerent;operaher pass a call to tors positions and above-each such jack I- provide, aabusy signal BS which is lighted while the trunk'C is iniuseso that no other operator will K attempt to: connect therewith. Two 'reflaysare. provided at the outgoing end of the trunk. for, controlling the signals BS,

said'relays being in the nature of line and en an opera ton'connec'ts with the trunk jack TJ the as- 's'ocia'ted cut-oflt'-.relay CO is'opera'ted over the sleeve strand and this lights all "of; the

associatedlamps B3,, -Also if the plug, of-

the trunk CisJin the jack; of a ealleduzline "and-.thef plug GP has; been withdrawn from the: trunk j ack. TJithen :theline relay LE ,is operated over the v,trunk co'nductor; to mains tain the; signals BS lighted until the trunk plug is removed. I also provide a repeating oil for the trunk circuit and a high resistbe seen that no matter which prevent the calling TS both relays ance' bridged relay H which relay. in ac- Cordance with well-known practice is of a high enough resistance to prevent the actuation of the tip relay CT of a connected cord B.

lVhenan operator inserts a plug CP in a trunk jack TJ, relay H energizes followed by the operation of an operators cut-in relay 0C which relay serves to connect the distant operators telephone 0 to the trunk circuit, this relay also serving to light the combined guard and disconnect lamp GI) which remains lighted until the trunk plug is inserted in'the jack of the called line. Upon the connection of the distant operators telephone 0 with the trunk the operators busy relay BO energizes to connect ground to the sleeve conductor of all of the idle incoming trunks terminating at this distant opera-tors position which ground connection serves to operate the line relays LR of these trunks and thereby light their associated busy signals BS so that nooriginating operators will attempt to connect to any ,of'thc trunks going to this busy distant operator, this busy condition being maintained until the operator has extended the call by inserting the trunk plugs TCP in the line jack of the wanted line. In connection with relay BO the conductor leading from its contact 22 is common to all of this operators trunk circuits. That is, there is a connection 23 extended from the alternate contact 22 of B0 to a normal contact 24 on each of the relays TS of this operators trunks. It will thus one of her trunks are used all of the idle ones terminating at her position are maintained busy as long as the relay B0 is energized.

As eachoperators telephone is common to both the operators cord crcuits B and the incoming trunk circuits C at her position it will be apparent, that ;relaykBO energizes each-time a link circuit is used, energizing when the incoming end of the link is connected with, and deenergized when the outgoing end of the link is connected with,- this period of energization of B0 maintaining all'thezdistant trunk jacks extending to her position busy; I

At the calling or outgoing end of trunk circuit C (which is preferably of the twoconductor type although my invention is not limited to this), I provide a trunk sleeve relay TS and an auxiliary trunk sleeve relay always operating together and being provided because there are more contacts to be controlled than good practice will permit to beplaced upon' 'a single electroma'gnet. A trunk tip supervisory relay TRT is also provided, and automatic party line ringing, andto this end I provide a ringing' key -RK and ringing control relay RCR energized when the ringing key is actuated. A trunk interrupter relay TIR is also provided Nil being adapted to alternately connect ringing current and the trunk tip relay to the tip conductorof the trunk. In connection with the trunk circuit I have also shown a meter device consisting of a meter-relay MR and a meter magnet MM Operation.

Having described in general the apparatus embodied in my preferred arrangement I will now describe more in detail the operation of the system.

Assuming that a call is initiated at substation A by the removal of the receiver thereat, line relay LR is energized over the calling line effecting the operation of line signals S. An operator inserts an answering plug AP into a jack J of the calling line connecting relays TE and CO in series and causing the energization of TE but not that of CO'whereupon the sleeve relay AS is connected to the sleeve conductor of the cord through alternate contact 1 causing the energization of AS and CO in series followed by the energization of the tip relay AT over the calling line. Relay AS therefore closes its alternate contact 2 effecting a locking circuit for itself through the sleeve conductor independent of alternate contact 1. The closing of alternate contact 3 of AS does not effect the lighting of supervisory lamp 4 on account of the interruption of normal contact 5. The closing of alternate contacts 6, 7, of AS connects operators telephone 0 in circuit with the cord through normal contacts 8, 9 of the calling sleeve relay CS.

Before proceeding further with the description of the connection I will refer briefly to the arrangement forexcluding operators who may subsequently connect to this same line Assuming that a second operator inserts a plug AP into another jack J of this calling line subsequent to the insertion of the first plug, this second operators telephone will not be connected to this calling line due to the fact that the test relay TE of the second cord will'not become energized because of the parallel circuit established through the comparatively low resistance relay AS of the first cord. Therefore the sleeve relay AS of the second cord does not energize and the second operator -receiving; no reply to her inquiry knows that the call..-

has been seized. 1

Again taking up the first connection above referred to, the first operator ascertains the number of the wanted subscriber and finding that the wanted line terminates at .a distant exchange, she will insert the calling plug CP into an idle trunk jack TJ leading to'the wanted exchange, such idle condition being indicated by the absence of the illumination of busy signals BS. Upon insertion of plug OP into the trunk jack, the circuit for relays CS and CO is established over the sleeve ing of alternate contact 12 establishes a circuit through normal contacts 13, 14: and 'supervisory lamp 15 effecting its illumination until the called subscriber responds as will be more clearly described.

Connection having been made to trunk C as described, sleeve relay CS and tip relay CT of cord circuit B are connected in series with the high resistance trunkrelay H, which relay is energized but due to its high resistance prevents the energization of CT. Responsive to the closing of alternate contact 14 of H a circuit for the operators connecting relay O0 is established whereby said relay energizes closing its alternate contact 15 and establishing a circuit for the guard lamp GD through normal contact 16 of TS to ground. The closing of alternate contacts 17, 18 of 0C connects the operators telephone 0 through normal contacts 20, 21 of sleeve relay TS to the trunk talking .conductors. At this time the operators busy relay B0 is connected through contacts 18 and 21 and then through the winding of trunk sleeve relay TS to battery causing the energization of B0 but its high resistance ing ground to its common conductors 23, the.

conductors 23 which extend to idle trunks being effective to cause the illumination of the busy signals BS, associated with the jacks of such idle trunks. This busy indication serves to keep other operators from extending connections to this busy operator. That is, while she is answering this trunk call it is desirable to keep otheroperators from extending trunk connections to her positions, such other operators in such case selecting trunks which extend to idle operators in the desired exchange. The circuit by which the busy lamps are maintained lighted may be traced from ground at alternate contact 22 of relay BO, conductors 23 to normal contacts 24 of all the idle trunk circuits at this operators position, sleeve conductor of such trunks C, normal contacts 11 and relays LE to battery. The relays LE of these trunks are thus energized closing their alternate contacts 25 and lighting the associated busy lamps BS. This ground connection from alternate contact 22 does not efiect the trunks which are included in taking connections between or to substations due to the fact that the relay TS of such trunks are energized cord circuit and connecting her operators telephone 0 to the calling end of the cord and thus into talking association with the operators telephone 0 at the distant exchange. The operator at Bnow orders the number of the wanted substation but due to the interruption of the talking strands B the calling subscriber does not hear this 'number as it is being passed along to the distant operator. The operator at B after having given the order, restores the orderwire key OW and the operator at C after testing the wanted line in the usual manner and finding it idle inserts the trunk plug TCP into a jack J thereof connecting the trunk sleeve relay TS and cut-off relay CO in series andefi'ecting theirenergization. 4 Upon energization of TS its normal contacts 20, 21 are interrupted effecting the deenergizations of the associated relay B0 and thus removing the busy condition of all of this operators idle incoming trunks by extinguishing their'signals BS. The interruption of contacts 20, 21 also disconnects the operators telephone and the closing of alternate contact 26 causes the energization of the auxiliary trunk sleeve relay TS whereupon its normal contact 24 is interrupted preventing any subsequent energization of relay BO from interfering with the conversational connection of this trunk. The closing of alternate contact 27 of TS establishes the continuity of the tip conductor of the trunk and the interruption of normal contact 16 eifaces guard lamp GD.

The operator at C now actuates the proper ringing button thereby connecting generator to the ringing conductor 28, the actuation of such button while in its fully actuated position, also effecting the closure of common contacts 29, 30 whereupon a circuit for the meter relay MB is established from battery through the winding of MR alternate contact'30, normal contacts 31, 32, conductor 33 and alternate contact 16 toground. Relay MR therefore energizes causing the operation. of meter magnet MM and a single operation of the meter to record the established connection. The closing ofthe alternate contact 29 of 'the ringing key establishes an energizing circuit for the ringing control relay ROB? traced from battery through the wind ing of said relay, alternate contact 29, normal contact 32, conductor 33 to groundat alternate contact 16. Relay RCR therefore closes its alternate contact 34 establishing a locking circuit for itself through said normal contact 32 to ground at alternate contact 16. Alternate contact 35 of EUR also closes establishing an operating circuit for the trunk interrupter relay TIR traced from battery through interrupter TI, relay TIR, alternate contacts 35 and 14 to ground. Relay TIR therefore alternately connects the ringing conductorsi28 and the tip trunk conductor and relay TRT to the called line, each energization of TRT being effective to cause the transmission of ringing current through alternate contact 37 and over the called line back through alternate contact 38 to battery and ground.

Upon response of the called subscriber and the first subsequent closure of normal contact 37, a circuit for the trunk tip relay T RT is established traced from ground through the winding thereof, alternate contact 27, normal contact 37 over the called line returning through the \vindin of trunk sleeve relay TS to battery. The tip relay TRT is therefore energized closing its alternate contact 38 thereby shunting relay H which deenergizes and due to the interruption of normal contact 32 of tip relay TRT, relay RCR is denergized and further operations of the interrupter relay are prevented. The closing of the shunt across the winding of relay H also establishes a low resistance path over the trunk circuit so that the tip relay CT of the cord is energized interrupting the circuit for the supervisory signal 15 which is thereby efi'aced. The subscribers are now connected over a conversational circuit traced over the heavily marked conductors.

After completing conversation the subscribers replace their receivers upon their respective switch-hooks, the replacing at called station D effecting the restoration of trunk tip relay TRT whereby the shunt is removed from around the winding of relay H so that its high resistance causes the restoration of the calling tip relay CT of cord circuit B. The restoration of CT closes an operating circuit for the supervisory lamp 15 through normal contacts 14, 13 and alternate contact 12. The replacing of the re ceiver at substation A effects the restoration of answering tip supervisory relay AT whereby a circuit for the supervisory lamp 4 is established through normal contact 5 and alternate contacts 3, 12 to ground lighting said lamp .4. It will be noted that link disconnect relay LD being in multiple with lamp 4 also energizes when relay AT restores, the energization of LD causing the disconnection of the link circuit at contacts 40, 41 so that the subscriber at A can recall without awaiting the removal of the answering plug from the jack. The closing of alternate contact 42 of relay LD establishes a locking circuit for the sleeve relay AS traced from battery through the winding of AS alternate contact 42, 3, 12 to ground. Thus'the supervisory lamps are maintained lighted until the cord is taken. down irrespective of whether the subscriber at A does or does not recall.

Theoperator at cord B noting the disconnect signal withdraws plugs AP and GP from their respective jacks, the restoration of plug GP permitting the deenergization of sleeve relay GS whereby the interruption of its alternate contact 12 allows the restoration of relays LD, TE and AS so that the cord B is again at normal.

Also upon the removal of the plug OP from the trunk jack TJ the trunk cut-ofi relay CO denergizes, but lamps BS are not efiected because line relay LE is connected to the sleeve conductor of the trunk and is energized over-a circuit traced to ground through alternate contact 24: of relay TS Thus the busy signals BS'of this trunk are maintained lighted, and remain so until the trunk plug TCP is removed from the jack of the called line. However, when the cord plug GP was removed from the trunk jack the bridge relay H of the trunk deener'gized interrupting the circuit of relay 0G which restores connecting disconnect lamp GD in circuit with battery and ground through normal contacts 15 and '82 and alternate contact 16 whereupon the operator withdraws the trunk plug from the jack of the called line. This last act permits of the restoration of relays TS and TS and the interruption of alternate contact 16 to TE; interrupts the circuit for lamp GD causing its efiacement. The interruption of alternate contact 24 of T5 removes ground from the sleeve conductor of the trunk causing the restoration of the trunk line relay LE and the efi'acement of the associated busy signals BS. The apparatus of the trunk being at normal it is now available for other connections. 4

From the above, it will be noted that from the time the cord plug CP is withdrawn until the trunk plug TGP is withdrawn, although the trunk or distant operator is busy in tam'ng down this connection, only the busy lamps of this trunk are maintained lighted as the period of disconnection is very short,

, In the preferred arrangement of the eye tern ll provide each operator with a number of cord circuitsB and also a number of trunk circuits 0 terminating at her position in plugs TCP which extend from outgoing trunk jacks TJ from-difierent exchanges. Thus each operator will also have anumber of outgoing trunks jacks TJ extending to other exchanges. In order that an operator who' seeks to extend a call over a trunk to the desired exchange who is idle, and in order to provide a more equal distribution of the trunked connections or extensions, 1

preferably arrange the busy signals so that when any operator is busy inthe act of answering any call, that is a local call at her position or a trunked call,'al1 trunk jacks at their exchanges leading to her position are maintained busy. Thus it will be seen that when a call is to be extended from a cord circuit B to a trunk circuit, the operator can tell at a glance which trunks lead to idle operators at the desired exchange. In this way the trunk calls will not pile up on one operator but will be distributed among the idle ones.

It will also be'apparent from the foregoing that in myimproved system the originating operator communicates with the distant operator over the connecting trunk which in this instance is also used as an orderwire for ordering up the connection with the distant subscriber. In this way I distinguish from the system wherein special orderwires are provided independent of the trunk circuits. Thus it will be seen that in my system instead of the originating operator communicating with a distant operator who assigns the trunk, the originating operator selects the trunk and then orders up the connection to the distant desired substation over the selected trunk. By means of the busy signals which are provided over the trunk jacks, the originating operator selects an idle trunk and upon plugging into the trunk jack automatically connects her cord circuit with the telephone of the selected operator, so that the actuation of the order wire key OW will immediately place the two operators telephones in communication. It must be apparent that with this arrangement great efiiciency of the trunks is tributing frames I have found allA operators have considerable idle time between calls and it will be seen from the foregoing that the trunk connections coming into the operators are extended to them only when idle so that what formerly was lost time is now used. for handling trunked connections Having thus described my invention what I claim as new and desire to secure by Letters Patent is: v i 1. A. telephone system comprising telephone lines terminating at an operators position, operators cord circuits for interconnecting said lines, trunk circuits extendmg from" said position to other operators positions, an operators telephone for the cord circuits and one for the trunk circuits,

means for automatically connecting and disconnecting the cord operators telephone and said cord circuits, and an orderwire key individual to each cord circuit whereby the cord operators telephone may be connected in circuit with the trunk operators telephone over a conversational circuit independent of that end of the cord circuit distant from the trunk.

2. A telephone system comprising telephone lines terminating at an operators position, trunk circuits extending from sald position to Other operators positions, cord circuits for interconnecting said lines or said lines and trunk circuits, an operators telephone for the cord circuits and one for the trunk circuits, automatic means for connecting the cord operators telephone with the cord circuits, telephone lines at said other operators positions, and orderwlre keys for said cord circuits for connectlng the operators telephone of a connected cord and a trunk over a conversational circuit including the cord and trunk but independent of that end of the cord distant from the' trunk.

3. A telephone system comprising telephone lines terminating at an operators position, trunk circuits extending from said position to other operators-pos1t1ons, telephone lines, terminating at such other positions, cord circuits for interconnectlng the first said lines or said lines and trunk circuits, an operators telephone for the cord circuits, automatic means for connecting the cordoperators telephone with the cord circuits when they are used for local connections, and orderwire keys for said cord circuits whereby a cord operator may order up a connection from, a line terminating at her position to a distant line over a cord and trunk circuit and prevent the subscriber at the calling line from hearing said order passed.

4. A telephone system comprising telephone lines terminating at an operators position, trunk circuits extending from said position to another operators position, telephone lines terminating at such other position, a cord circuit for interconnecting the first said lines or said lines and trunk circuits, an' operators telephone, automatic means for connecting and disconnecting said operators telephone and said cord circuit when it is used to establish said first connections, and means whereby when a connection is to be extended from a calling line over a cord and a trunk circuit to a distant line, the cord operator may order up the connection to the distant line over a connected cord and trunk to the exclusion of the calling line.

5. A telephone system comprising telephone lines, a trunk circuit adapted for use in connecting said lines to other telephone lines, a cord circuit for interconnecting the first said lines or said lines and trunk circuit, an operators telephone and means for automatically connecting it to the trunk when'connection is made with the trunk by the cord when a connection is to be estab lished between a calling line over a cord and trunk circuit to a distant line, and an orderwire key for the cord having circuit connections whereby the cord operator may communicate with the trunk operator over the connected cord and trunk to order up the connection to the distant line to the ex- 1 clusion of the calling line.

6. A telephone system comprisin telephone lines, a trunk circuit adapted or use in connecting said lines to other telephone lines, a cord circuit for connecting the said first lines with said trunk circuit, an operators telephone, means for automatically connecting said operators telephone to the trunk when connection is made with the trunk by the cord when a connection is to be extended to a distant line, and a key for the cord having circuit connections whereby the operator may communicate with the trunk operator to order up the connection to the distant line.

7. A telephone system comprising telephone lines, a link circuit and a trunk circuit for interconnecting said lines, an operators telephone for the link circuit, means for automatically connecting the telephone with the link circuit, automatic means for disconnecting the operators telephone from the link circuit, and a manual key for connectin the operators telephone with the link circuit to the exclusion of the calling subscriber when said link circuit is connected to the said trunk circuit so that the operator may communicate with an operator associated with the said trunk circuit.

8. A telephone system comprising telephone lines, an operators link circuit and a trunk circuit for interconnectingsaid lines, means responsive to the connection of said link circuit to a calling line for connecting the operators telephone with the link circuit, means responsive to the connection of the link circuit with the trunk circuit for automatically disconnecting the operators telephone from the link circuit, and a key for connectin the operators telephone with the link circuit to the exclusion of the calling line so that the operator may order up a connection.

9. A telephone system comprising subscribers lines provided with multiple answering jacks, operators link circuits divided into groups, an operators telephone for each group of link circuits, means for permitting an operator to connect her telephone with a calling one of said lines to the exclusion of the other operators, a trunk circuit, anda key for connecting an operators telephone with the trunk circuit to the exclusion of the calling line.

10. A telephone system comprising subscribers lines provided with multiple answering terminals,

link circuits divided into groups, an operators telephone for each group of link circuits, automatic means for permitting an operator to connect her telephone to one of said multiple terminals of a calling line to the exclusion of the remaining operators, a trunk circuit extending to a second exchange and an orderwire key for said link circuit having circuit connections whereby the link circuit operator may communicate with the trunk operator to order up a connection to the exclusion-of the calling line.

' 11. A combination with a calling telephone line, a plurality of connecting terminals for said line located at a central office switchboard operators link circuits including means whereby any one of said link circuits may be connected to one of said line terminals to the exclusion of the remaining link circuits, a trunk circuit, and means whereby the link circuit operator may order up a connection over a trunk circuit to the exclusion of the calling line.

12. A-telephone system including a calling subscribers line provided with terminals through which said line may be seized to extend a call, link circuits provided with answering terminals, means for preventing the operative connection of more than one of said link circuits to said line when said line signals for a connection, a trunk circuit, and means for permitting the link circuit operator to connect her telephone to the trunk circuit to the exclusion of the calling line.

13. A telephone system including telephone lines, each having a plurality of connecting terminals, link circuits having manually controlled answering terminals for connection with said line terminals, means to prevent the operative association of more than one answering terminal with the terminals of any one line, a trunk circuit extending to a second exchange, and a key for said connected operators link circuit for permitting her to connect to said frank circuit to the exclusion of the calling Signed by me at Chicago, county of Cook and State of Illinois, in the presence of two witnesses. Y

HIRAM D. CURRIER. Witnesses M. R. Roorrronn, WM. BERGHAHN. 

